Gtk.Notebook.prototype.get_menu_label_text

function get_menu_label_text(child:Gtk.Widget):String {
    // Gjs wrapper for gtk_notebook_get_menu_label_text()
}

Retrieves the text of the menu label for the page containing child.

child: the child widget of a page of the notebook.
Returns: the text of the tab label, or null if the widget does not have a menu label other than the default menu label, or the menu label widget is not a Gtk.Label. The string is owned by the widget and must not be freed.